The BBC4 controller, Janice Hadlow, is tipped as the frontrunner to take over BBC2 following Roly Keating's announcement today that he is to step down as controller.

Keating, the BBC's current longest-serving channel controller, will leave his role in October to take on the new job of director of archive content.

The BBC has said the BBC2 job will not be officially advertised until the autumn, but leading candidates are already emerging.

Hadlow is seen as the obvious choice after her successful stint at BBC4, which she took over after Keating moved to BBC2.

The current second longest-serving controller after Keating, her four years at BBC4 have seen her broaden the channel's appeal and make it more accessible while staying true to its intelligent roots.

It pulled in its highest ever audience in March when a drama about the warring stars of Steptoe and Son picked up 1.4 million viewers, eclipsing the previous record of 1.1 million that period drama Fanny Hill attracted in October last year.

Hadlow, a former Channel 4 head of specialist factual, only recently returned to her role after taking an extended sabbatical to write a book about George III.

Janice has got tuppence in her budget but she has done amazing stuff," said a source. "She has managed to give the channel a voice."

Newsnight editor Peter Barron is also seen as a leading candidate, with speculation mounting for some time that he has been looking to move on from the BBC2 news programme.

Sources have said that Barron, who has edited Newsnight for four years, was recently set to take a major role at an independent production company, although the move never came off.

Insiders have said the BBC is keen to keep hold of him, although his stock was said to have fallen after his outburst at last year's MediaGuardian Edinburgh International Television Festival, where he spoke out against a proposed BBC climate change special.

"There are lots of vibes about Peter moving on to another job, and the BBC2 role would make sense for him," one BBC source said.

"He would make a fantastic controller. He is a visionary. It would be a big signal for creativity and seriousness for the channel. It would be a brave thing for the BBC to do."

However, another source said it might be too early for Barron to step into a controller's job.

"Peter will do one more job before becoming a channel controller," the source said. "Newsnight to channel controller is quite a big leap, but he is clearly a rising star."

Barron has previously worked on Channel 4 News and Tonight with Trevor McDonald, where he was deputy editor, as well as editing the BBC2 current affairs drama documentary series If.

Other leading internal candidates include the head of in-house knowledge commissioning, Emma Swain, and Richard Klein, who heads the independent commissioning team for knowledge.

Other candidates include the head of the multimedia newsroom, Peter Horrocks, and the controller of entertainment commissioning, Elaine Bedell.

The BBC's controller of knowledge commissioning, George Entwistle, is also seen as a candidate, although he would be more likely to get the BBC4 job if Hadlow were given BBC2, after he successfully stood in for her during her sabbatical.

External candidates include the ITV director of factual and daytime, Alison Sharman, a former BBC controller of daytime.

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